Bone Regulation Part 1

welcome to another path Oh video today let's talk about regulation of bone remodeling it may seem like the adult skeleton doesn't change very much over time but inside your bones cells are constantly busy at work breaking down bone and building it up in a process called bone remodeling in fact 10% of your skeleton is replaced every year that means that after ten years you have an entirely different skeleton bone remodeling is also an important process that can repair Micra damage or change the shape and strength of bones in response to structural and mechanical demands here the skeleton is applying weight-bearing forces that will result in buildup of more bone and will reduce the risk of fractures to understand what determines whether the skeleton gets stronger or a weaker it's important to know there are cells called osteoblasts which produce the proteins and minerals which make up the bone matrix and cells that are responsible for bone breakdown or resorption called osteo class together the activity of osteoblasts and osteoclasts on the bone surface is known as bone multicellular unit or B mu B mu activity is regulated by important cell to cell interactions one of the better understood interactions is rank rank al OPG signaling pathway this system regulates osteoclast differentiation and activation the rank rank al OPG signaling pathway starts with an osteoblast or an osteochondral progenitor cell this cell will express what is called rank L which stands for receptor activator for nuclear factor Kappa B ligand an osteoclast precursor cell expresses rank or receptor activator for nuclear factor Kappa B when a rank L rank interaction occurs the rank signaling will activate a transcription factor known as NF kappa-b which stands for nuclear factor Kappa B NF kappa-b is important for the survival and production of osteo class osteoporotic Garen or LPG is a decoy receptor produced by osteoblasts that will bind to rank L and prevent rank rank L interactions effectively blocking the signal that triggers the production of osteo class knowing this do you think high levels of OPG would increase or decrease bone resorption if you answered decrease than you are correct levels of OPG and rank L can change OPG is increased by mechanical strain and sex hormones OPG is decreased by parathyroid hormone which is produced by the four small glands on the posterior aspect of the thyroid gland opg is also decreased by glucocorticoids so remember high levels of P th and glucocorticoids favor osteoclast activity over osteoblast activity also know rank L expression is increased by P th and glucocorticoids rank L expression is decreased by sex hormones so to summarize know that sex hormones and mechanical strain will increase osteoblast activity compared to osteoclast activity favoring bone retention this concludes the video bone regulation part 1 thanks for watching

Channel: PhysioPathoPharmaco

Views: 11,314

Keywords: regulation of bone remodeling, weight bearing forces, skeleton, osteoblast, osteoclast, bone multicellular unit, signaling, receptor activator nuclear factor kappa b ligand, parathyroid gland

Id: MyKswPXHjKs

Length: 5min 22sec (322 seconds)

Published: Sat Jul 15 2017